This chapter is the first chapter of the part - 1. This part prepares you for Deep learning and in this chapter Linear Algebra is covered. The author advice you to skip the chapter if you are already familiar with the concepts. Also it is not that you can become Gilbert Strang after reading this chapter! The chapter is so concise that what may be relevant to our future acquaintance with the book are only present here. Only at the end of the chapter some concepts author speaks on the application part. The focus is on mathematical concepts involving Linear Algebra. Though Science and Engineering use Linear Algebra efficiently, Computer scientist have lesser experience with it. This is the motivation of the chapter and if you have experience it then author provides you with a reference (The Matrix Cookbook - Petersen and Pedersen, 2006) and waves you good bye to meet in the next chapter. Definitions ...